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CN112072940B - Active modular converter chain, converter control method and device and electronic equipment - Google Patents

Active modular converter chain, converter control method and device and electronic equipment Download PDF

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Publication number
CN112072940B
CN112072940B CN202010934017.XA CN202010934017A CN112072940B CN 112072940 B CN112072940 B CN 112072940B CN 202010934017 A CN202010934017 A CN 202010934017A CN 112072940 B CN112072940 B CN 112072940B
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energy
chain
energy storage
sub
converter
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CN202010934017.XA
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CN112072940A (en
Inventor
谢晔源
王宇
盛晓东
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NR Electric Co Ltd
NR Engineering Co Ltd
Changzhou NR Electric Power Electronics Co Ltd
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NR Electric Co Ltd
NR Engineering Co Ltd
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Priority to CN202010934017.XA priority Critical patent/CN112072940B/en
Publication of CN112072940A publication Critical patent/CN112072940A/en
Priority to PCT/CN2021/116978 priority patent/WO2022052916A1/en
Priority to JP2023507747A priority patent/JP2023537343A/en
Priority to DE112021003103.1T priority patent/DE112021003103T5/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
    • H02M1/0077—Plural converter units whose outputs are connected in series
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
    • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
    • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
    • H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
    • H02H7/1213—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for DC-DC converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H02M1/325—Means for protecting converters other than automatic disconnection with means for allowing continuous operation despite a fault, i.e. fault tolerant converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of DC power input into DC power output
    • H02M3/22—Conversion of DC power input into DC power output with intermediate conversion into AC
    • H02M3/24—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters
    • H02M3/28—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC
    • H02M3/325—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of DC power input into DC power output
    • H02M3/22—Conversion of DC power input into DC power output with intermediate conversion into AC
    • H02M3/24—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters
    • H02M3/28—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC
    • H02M3/325—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33507—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
    • H02M3/33523—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters with galvanic isolation between input and output of both the power stage and the feedback loop
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
    • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
    • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H02M7/49—Combination of the output voltage waveforms of a plurality of converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/38—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to both voltage and current; responsive to phase angle between voltage and current
    • H02H3/382—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to both voltage and current; responsive to phase angle between voltage and current involving phase comparison between current and voltage or between values derived from current and voltage
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for AC mains or AC distribution networks
    • H02J3/28—Arrangements for balancing of the load in a network by storage of energy
    • H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
    • H02M1/007—Plural converter units in cascade

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)
  • Rectifiers (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

The application provides an active modular commutation chain control method, which comprises the steps of calculating the maximum value of active power output by a commutation chain according to the number of energy storage sub-modules and the number of energy-free sub-modules; correcting the received active power instruction according to the active power maximum value to obtain an active power correction instruction; correcting the received reactive power instruction according to the active power correction instruction to obtain a reactive power correction instruction; the control system distributes the active power correction instruction to the energy storage commutation chain, and distributes the reactive power correction instruction to the non-energy storage commutation chain and the energy storage commutation chain; the energy storage commutation chain executes closed-loop control according to the distributed active power correction instruction and reactive power correction instruction; and the non-energy-storage current conversion chain executes closed-loop control according to the distributed reactive power correction instruction. And correcting the power instruction according to the output power capability of the current conversion chain, so that the control target is prevented from exceeding the operation range, and the reliability is improved.

Description

Active modular converter chain, converter control method and device and electronic equipment
Technical Field
The application relates to the technical field of high-power electronic converter, in particular to an active modular converter chain control method and device, a converter control method and device and electronic equipment.
Background
In the technical field of high-capacity high-power electronic current transformation, a multi-level current converter integrates an energy storage device into a sub-module by utilizing a modular cascade technology, has the advantages of high modularization degree, good harmonic characteristic, equivalent switching frequency and the like, and is a standard topology in the field of high-voltage power electronics at present. The energy storage unit is integrated in the modularized multi-level converter as a sub-module, so that alternating current-direct current power conversion and energy storage can be realized at the same time.
The produced active modular converter is a feasible scheme which can effectively meet the access requirement of an energy storage system and relieve or isolate fault propagation between alternating current and direct current systems. The multi-level converter with the energy storage unit needs to consider the condition of energy storage unit failure or power unit failure. The submodules in different states have different operating characteristics, for example, the normal submodules of the energy storage unit can provide active power and reactive power, and the fault of the energy storage unit or the submodules without the energy storage unit can only play the roles of regulating the reactive power and supporting alternating voltage.
In the prior art, a control concept of a capacitor submodule and an energy storage submodule is introduced into a single-phase power control method of a hybrid unit cascade H-bridge energy storage system, a working vector diagram of the system is analyzed, however, the number of various types of submodules is neglected to be dynamically changed, and the active power and reactive power regulation capacity of a converter chain is changed along with the change of the number. In this case, the commutation chain may not be able to perform as commanded due to limitations in power regulation capabilities when it receives control commands. If the instruction is still executed according to the original instruction, a series of problems such as system control instability and the like can be caused.
Disclosure of Invention
Based on this, the present application provides an active modular commutation chain control method, wherein the commutation chain comprises,
n sub-modules connected in series, wherein N is an integer greater than or equal to 2;
the N sub-modules comprise N1Energy storage submodule N2Each energy-free submodule and N3A fault bypass submodule, N1、N2Is an integer of 1 or more, N3Is an integer of 0 or more;
the energy storage sub-module comprises a power unit, an isolation unit and an energy storage unit; said N is1Each energy storage submodule forms an energy storage commutation chain;
the non-energy-storage sub-module comprises a power unit; said N is2Non-energy-storage commutation formed by non-energy-storage sub-modulesA chain;
the power cell includes a bypass switch;
the method for controlling the converter chain is characterized by comprising the following steps:
according to the number N of the energy storage sub-modules1And the number N of said energy-free submodules2Calculating the maximum value of the active power output by the current conversion chain;
correcting the received active power instruction according to the active power maximum value to obtain an active power correction instruction;
correcting the received reactive power instruction according to the active power correction instruction to obtain a reactive power correction instruction;
distributing the active power correction instruction to the energy storage commutation chain, and distributing the reactive power correction instruction to the non-energy storage commutation chain and the energy storage commutation chain;
the energy storage commutation chain executes closed-loop control according to the distributed active power correction instruction and reactive power correction instruction; and the non-energy-storage current conversion chain executes closed-loop control according to the distributed reactive power correction instruction.
According to some embodiments of the application, the number N of the energy storage sub-modules is1And the number N of said energy-free submodules2Calculating the maximum value of the active power output by the commutation chain, including:
calculating the output voltage V of the energy storage commutation chaint；
With the collected grid voltage effective value vector VsThe starting end of the device is a circle center and VtForming a first circle as a radius;
calculating the output voltage V of the non-energy-storage current conversion chainc；
With collected grid voltage VsThe end of the effective value vector is the center of a circle, VcIs a radius, forming a second circle;
and calculating the maximum active power value according to the position relation of the first circle and the second circle.
According to some embodiments of the application, the energy storage sub-moduleNumber N of1And the number N of said energy-free submodules2Calculating the maximum value of the active power output by the commutation chain, and further comprising:
calculating the output voltage V of the energy storage commutation chain according to the following formulatAnd the output voltage V of the non-energy-storage converter chainc：
Vt＝N1VOtmt；
Vc＝N2VOcmc；
Wherein VOtIs the DC voltage of the energy storage submodule, mtThe modulation ratio of the energy storage submodule is used; vOcIs the DC voltage of the no-energy-storage submodule, mcAnd modulating the ratio for the energy-free submodule.
According to some embodiments of the application, the calculating the active power maximum value according to the positional relationship between the first circle and the second circle comprises:
when the first circle comprises the second circle, calculating the maximum value P of the active power according to the following formulamax：
Pmax＝VSIe，
Wherein, VsFor collected grid voltage vectors, IeThe rated current of the converter chain is obtained;
when the second circle comprises the first circle, calculating the maximum value P of the active power according to the following formulamax：
Pmax＝VSIesinθ，
Wherein θ is a tangent vector from the center of the second circle to the first circle and a vector VsThe included angle of (A);
when the first circle intersects with the second circle, determining the maximum value of the active power according to the intersection point position;
when the first circle and the second circle are tangent, the maximum active power value is 0;
when the first circle and the second circle are separated from each other, the commutation chain is in a fault state.
According to some embodiments of the application, the determining the active power maximum value according to the intersection position when the first circle intersects the second circle comprises:
calculating the maximum value P of the active power according to the following formulamax：
When theta is more than or equal to 90 degrees, Pmax＝VSIe；
When theta is less than 90 DEG, Pmax＝VSIesinθ；
Wherein θ is a vector from the center of the second circle to the intersection and a vector VsThe included angle of (a).
According to some embodiments of the application, the modifying the received active power command according to the active power maximum value to obtain an active power modification command includes:
judging the maximum value P of the active powermaxWhether or not greater than the active power command Pref；
When P is presentmax≥PrefThe active power modification instruction Pref’＝Pref；
When P is presentmax<PrefThe active power modification instruction Pref’＝Pmax。
According to some embodiments of the application, modifying the received reactive power command according to the active power modification command to obtain a reactive power modification command includes:
according to the active power correction instruction Pref' and apparent power S of the converter chain, and calculating the maximum value Q of the reactive power of the converter chain according to the following formulamax：
Figure GDA0003323604070000041
Judging the maximum value Q of the reactive powermaxWhether or not greater than the reactive power command Qref；
When Q ismax≥QrefThen, the reactive power correction command Qref’＝Qref；
When Q ismax<QrefThen, the reactive power correction command Qref’＝Qmax。
According to some embodiments of the application, assigning the reactive power correction instruction to the non-energy-storage commutation chain and the energy-storage commutation chain comprises:
according to the active power correction instruction Pref'. the reactive power correction command Qref' and grid voltage effective value vector VsCalculating the current effective value of the current conversion chain;
according to the formula VsPhi is arctan (Q)ref’/Pref') determining the direction and thus the vector of current effective values Is；
When the current effective value vector IsOr the extension line of the reactive power correction command Q is intersected or tangent with the second circleref' all assigned to said non-energy-storing commutation chain;
when the current effective value vector IsOr when the extension line of the second reactive power correction instruction is separated from the second circle, distributing the second reactive power correction instruction Q to the energy-free commutation chain2ref＝Vc×IsA first reactive power modification command Q assigned to said energy storage commutation chain1ref＝Qref’-Q2ref。
According to some embodiments of the application, assigning the reactive power correction instruction to the non-energy-storage commutation chain and the energy-storage commutation chain comprises:
and distributing the reactive power correction instruction to the energy storage commutation chain and the energy-free commutation chain according to the principle that the efficiency of the power unit is optimal.
According to some embodiments of the present application, the energy storage sub-module and the non-energy storage sub-module may be switched with each other; the energy storage sub-module or the non-energy storage sub-module may be converted to a fault bypass sub-module.
According to some embodiments of the application, the energy storage commutation chain performs closed-loop control according to the distributed active power correction command and reactive power correction command, including:
taking the distributed active power correction instruction and reactive power correction instruction as an outer loop control target;
obtaining a current instruction value of an inner ring by a regulator according to the difference value between the outer ring control target and the measured value;
obtaining an output voltage set value by a difference value between the current instruction value and the current measured value through a regulator;
distributing the given value of the output voltage to each energy storage sub-module;
and each energy storage sub-module controls the output voltage according to the given value of the output voltage.
According to some embodiments of the application, the energy-free commutation chain performs closed-loop control according to the distributed reactive power correction instruction, including:
taking the direct-current voltage average value of the non-energy-storage converter submodule and the distributed reactive power as an outer ring control target;
obtaining a current instruction value of an inner ring by a regulator according to the difference value between the outer ring control target and the measured value;
the difference value between the current instruction value and the measured value is adjusted by a regulator to obtain an output voltage set value;
distributing the given value of the output voltage to each energy-free submodule;
and each energy-free sub-module controls the output voltage according to the given value of the output voltage.
According to some embodiments of the present application, the isolation unit comprises: an isolation switch and/or a DC/DC loop with an isolation function.
According to some embodiments of the application, the power unit comprises a dc capacitor and a bridge circuit, the bridge circuit comprising a half-bridge circuit composed of two sets of power semiconductor devices or a full-bridge circuit composed of four sets of power semiconductor devices.
According to some embodiments of the present application, the method for controlling a converter chain further comprises:
when an energy storage unit in the energy storage sub-module fails, the isolating switch is separated or the DC/DC loop is locked, and the energy storage sub-module is converted into an energy-free sub-module;
updating the number N of the energy storage sub-modules1And the number N of said energy-free submodules2；
And repeating the steps in the commutation chain control method.
According to some embodiments of the present application, the method for controlling a converter chain further comprises:
when a power unit in the energy storage sub-module fails, the bypass switch is closed, and the energy storage sub-module is converted into a fault bypass sub-module;
when a power unit in the non-energy-storage sub-module fails, the bypass switch is closed, and the non-energy-storage sub-module is converted into a fault bypass sub-module;
updating the number N of the energy storage sub-modules1And the number N of said energy-free submodules2；
And repeating the steps in the commutation chain control method.
The present application further provides an active modular converter chain control method, wherein the converter chain comprises,
n sub-modules connected in series, wherein N is an integer greater than or equal to 2;
the N sub-modules comprise N1Energy storage submodule N2Each energy-free submodule and N3A fault bypass submodule, N1、N2Is an integer of 1 or more, N3Is an integer of 0 or more;
the energy storage sub-module comprises a power unit, an isolation unit and an energy storage unit; said N is1Each energy storage submodule forms an energy storage commutation chain;
the non-energy-storage sub-module comprises a power unit; said N is2Each energy-free submodule forms an energy-free commutation chain;
the power cell includes a bypass switch;
the commutation chain control method comprises the following steps:
according to the number N of the energy storage sub-modules1And the number N of said energy-free submodules2Respectively calculating the output voltage V of the energy storage commutation chaintAnd the output voltage V of the non-energy-storage converter chainc；
With the collected grid voltage effective value vector VsRespectively takes the initial end as the circle center and respectively takes Vt、VcForming a first circle and a second circle for the radius, and calculating the maximum value P of the active power output by the commutation chain according to the position relation of the first circle and the second circlemax；
According to the maximum value P of active powermaxFor received active power command PrefCorrecting to obtain an active power correction instruction Pref’；
According to the active power correction instruction Pref' and apparent power S of said converter chain, for received reactive power command QrefCorrecting to obtain a reactive power correction instruction Qref’；
Distributing an active power correction instruction Pref' to the energy storage commutation chain;
according to the active power correction instruction Pref', reactive power correction command Qref' and a vector of voltage effective values VsCalculating the current I of the converter chainsValue and direction, and according to current IsDetermining a reactive power correction command Q according to the position relation between the value and the direction and the second circleref' distribution principle;
according to the distribution principle, correcting the reactive power instruction Qref' assigning to the non-energy-storage commutation chain and the energy-storage commutation chain;
and the energy storage commutation chain and the non-energy storage commutation chain execute closed-loop control according to the distributed active power correction instruction and/or reactive power correction instruction.
The present application further provides a method for controlling an active modular converter, wherein the converter comprises three active modular converter chains, respectively A, B, C three-phase converter chains, wherein the converter chains comprise,
n sub-modules connected in series, wherein N is an integer greater than or equal to 2;
the N sub-modules comprise N1Energy storage submodule N2Each energy-free submodule and N3A fault bypass submodule, N1、N2Is an integer of 1 or more, N3Is an integer of 0 or more;
the energy storage sub-module comprises a power unit, an isolation unit and an energy storage unit; said N is1Each energy storage submodule forms an energy storage commutation chain;
the non-energy-storage sub-module comprises a power unit; said N is2Each energy-free submodule forms an energy-free commutation chain;
the power cell includes a bypass switch;
the converter control method comprises the following steps:
respectively reading the number N of energy storage sub-modules of the A, B, C three-phase converter chain1A、N1B、N1CAnd the number N of energy-storage-free sub-modules2A、N2B、N2C；
Respectively adjusting the number of energy storage submodules and the number of energy-free submodules in the A, B, C three-phase commutation chain, so that the number of the energy storage submodules in the A, B, C three-phase commutation chain is N1minThe number of the energy-storage-free sub-modules is N2minAnd the following conditions are satisfied:
N1min＝min(N1A；N1B；N1C)
N2min＝min(N2A+N1A-N1min；N2B+N1B-N1min；N2C+N1C-N1min)；
according to the number N of the energy storage sub-modules of the A, B, C three-phase converter chain1minAnd the number N of energy-storage-free sub-modules2minExecuting the above-mentioned commutation chain control method, so that the A, B, C three-phase commutation chain outputs active power balance;
and when the number of the energy storage sub-modules or the number of the energy storage sub-modules of the A, B, C three-phase converter chain is changed, repeating the steps.
The A, B, C three-phase converter chain output active power balance in the converter chain control method includes: the active power output by each A, B, C three-phase converter chain is equal.
The present application further provides an active modular converter chain control apparatus, wherein the converter chain comprises,
n sub-modules connected in series, wherein N is an integer greater than or equal to 2;
the N sub-modules comprise N1Energy storage submodule N2Each energy-free submodule and N3A fault bypass submodule, N1、N2Is an integer of 1 or more, N3Is an integer of 0 or more;
the energy storage sub-module comprises a power unit, an isolation unit and an energy storage unit; said N is1Each energy storage submodule forms an energy storage commutation chain;
the non-energy-storage sub-module comprises a power unit; said N is2Each energy-free submodule forms an energy-free commutation chain;
the power cell includes a bypass switch;
the commutation chain control device includes:
an active power maximum value calculation module used for calculating the number N of the energy storage sub-modules1And the number N of said energy-free submodules2Calculating the maximum value of the active power output by the current conversion chain;
the active power instruction correction module is used for correcting the received active power instruction according to the maximum value of the active power to obtain an active power correction instruction;
the reactive power instruction correction module is used for correcting the received reactive power instruction according to the active power correction instruction to obtain a reactive power correction instruction;
the power instruction distribution module is used for distributing the active power correction instruction to the energy storage commutation chain and distributing the reactive power correction instruction to the non-energy-storage commutation chain and the energy storage commutation chain;
and the power instruction execution module is used for executing closed-loop control by the energy storage commutation chain according to the distributed active power correction instruction and reactive power correction instruction and executing closed-loop control by the non-energy storage commutation chain according to the distributed reactive power correction instruction.
According to some embodiments of the present application, the commutation chain control apparatus further comprises:
the first control submodule controls the energy storage commutation chain;
the second control submodule controls the non-energy-storage current conversion chain;
and the commutation chain control device coordinates the input and the output of the first control submodule and the second control submodule.
The present application further provides an active modular converter control arrangement wherein said converter comprises three active modular converter chains, respectively A, B, C three-phase converter chains, said converter chains comprising,
n sub-modules connected in series, wherein N is an integer greater than or equal to 2;
the N sub-modules comprise N1Energy storage submodule N2Each energy-free submodule and N3A fault bypass submodule, N1、N2Is an integer of 1 or more, N3Is an integer of 0 or more;
the energy storage sub-module comprises a power unit, an isolation unit and an energy storage unit; said N is1Each energy storage submodule forms an energy storage commutation chain;
the non-energy-storage sub-module comprises a power unit; said N is2Each energy-free submodule forms an energy-free commutation chain;
the power cell includes a bypass switch;
wherein the inverter control device includes:
the submodule quantity reading module is used for respectively reading the quantity of the energy storage submodules and the quantity of the energy-free submodules of the A, B, C three-phase commutation chain;
the submodule quantity adjusting module is used for respectively adjusting the quantity of the energy storage submodules and the quantity of the energy-free submodules in the A, B, C three-phase converter chain;
and the power correction and distribution module is used for executing the commutation chain control method according to the energy storage submodule number and the energy-free submodule number of the A, B, C three-phase commutation chain.
The present application further provides an active modular converter control electronics comprising: one or more processors; storage means for storing one or more programs; when executed by the one or more processors, cause the one or more processors to implement the converter control method described above.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without exceeding the protection scope of the present application.
FIG. 1A shows a schematic diagram of an active modular inversion chain structure according to an example embodiment of the present application;
FIG. 1B shows a schematic diagram of an isolation cell structure according to an example embodiment of the present application;
FIG. 2 shows a flow chart of a commutation chain control method according to an example embodiment of the present application;
FIG. 3A shows a schematic view of a first positional relationship of a first circle and the second circle according to an example embodiment of the present application;
FIG. 3B shows a schematic diagram of a second positional relationship of the first circle and the second circle according to an example embodiment of the present application;
FIG. 3C shows a third positional relationship diagram of the first circle and the second circle according to an example embodiment of the present application;
FIG. 3D shows a fourth schematic positional relationship of the first circle and the second circle according to an example embodiment of the present application;
FIG. 3E shows a fifth schematic positional relationship of the first circle and the second circle, according to an example embodiment of the present application;
FIG. 4A shows a schematic diagram of a first intersection location according to an example embodiment of the present application;
FIG. 4B shows a second intersection location diagram in accordance with an example embodiment of the present application;
FIG. 4C shows a third intersection location diagram in accordance with an example embodiment of the present application;
FIG. 5A shows a schematic diagram of reactive power distribution according to a first example embodiment of the present application;
fig. 5B shows a reactive power distribution schematic according to a second example embodiment of the present application.
FIG. 6 shows a flow chart of a method of commutation chain control according to another example embodiment of the present application;
fig. 7 illustrates a flow chart of a converter control method according to an example embodiment of the present application;
fig. 8 shows a block diagram of a commutation chain control apparatus according to an exemplary embodiment of the present application;
fig. 9 is a block diagram showing a configuration of a converter control apparatus according to an exemplary embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It will be understood that, although the terms first, second, etc. may be used herein to describe various components, these components should not be limited by these terms. These terms are used to distinguish one element from another. Thus, a first component discussed below may be termed a second component without departing from the teachings of the present concepts. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Those skilled in the art will appreciate that the drawings are merely schematic representations of exemplary embodiments, which may not be to scale. The blocks or flows in the drawings are not necessarily required to practice the present application and therefore should not be used to limit the scope of the present application.
The invention provides an active modular converter chain control method aiming at the problems that the existing active modular converter chain control is only based on ideal state calculation and does not consider the limitation of the self-regulation capability of a converter chain, and the like, wherein a control instruction is corrected according to the self state of the converter chain so as to ensure that the converter chain can normally run at the maximum capability; meanwhile, reasonable instruction distribution is carried out on the submodules of two different types, so that the operation of the current conversion chain is ensured to be in the optimal state.
The technical solution of the present application will be described in detail below with reference to the accompanying drawings.
FIG. 1A shows a schematic diagram of an active modular inversion chain structure according to an example embodiment of the present application; fig. 1B illustrates a schematic diagram of an isolation cell structure according to an example embodiment of the present application.
The method for controlling the converter chain is suitable for the active modular converter chain 1000 shown in fig. 1A. The active modular converter chain 1000 includes N sub-modules, N respectively, connected in series1 Energy storage submodule 100, N2Each non-energy-storage submodule 200 and N3A fault bypass sub-module (not shown). N is an integer of 2 or more, N1、N2Is an integer of 1 or more, N3Is an integer of 0 or more. The positions of the energy storage sub-modules 100 and the energy-free sub-modules 200 in the commutation chain can be continuous, that is, the sub-modules of the same type are connected together; or discontinuous, that is, two sub-modules of different types are inserted in the converter chain. The fault bypass submodule can be arranged at any position in the converter chain.
The energy storage submodule 100 comprises a power unit 110, an isolation unit 120 and an energy storage unit 130; said N is1And the energy storage sub-modules form an energy storage commutation chain. The non-energy-storage submodule 200 includes a power unit 210; the N2 energy-free submodule 200 forms an energy-free converter chain. According to some embodiments of the present application, the non-energy-storage submodule 200 may further include an energy storage cut out by the isolation unitAnd (4) energy units. As in the embodiment shown in fig. 1, the non-energy-storing submodule 200 comprises a power cell 210.
The active modular converter chain 1000 also includes a control system (not shown) for controlling the operation of the converter chain. The control system further comprises a first control system and a second control system which are respectively connected with the energy storage commutation chain and the energy-free commutation chain.
The power unit 110 is used for implementing ac-dc conversion, and includes a bypass switch 111, a bridge circuit, and a dc capacitor 113. The bridge circuit includes a full bridge circuit composed of four sets of power semiconductor devices (S1, S2, S3, S4). According to further embodiments of the present application, the bridge circuit may also comprise a half-bridge circuit formed by two sets of power semiconductor devices.
Referring to fig. 1B, the isolation unit 120 may include an isolation switch 121 and/or a DC/DC loop 122 having an isolation function. According to an example embodiment of the present application, a DC/DC loop includes a DC/AC inverting unit, an isolation transformer, and an AC/DC rectifying unit. When the energy storage unit in the energy storage submodule has a fault, the isolating switch in the isolating unit is separated, or the DC/DC loop is locked, and the energy storage submodule is converted into an energy-free submodule.
Fig. 2 shows a flow chart of a commutation chain control method according to an example embodiment of the present application.
According to a first aspect of the present application, there is provided an active modular converter chain control method, as shown in fig. 2, the converter chain control method includes:
in step S210, according to the number N of the energy storage sub-modules1And the number N of said energy-free submodules2And calculating the maximum value of the active power output by the commutation chain. According to some embodiments of the present application, the process of calculating the maximum value of the active power output by the commutation chain is:
calculating the output voltage V of the energy storage commutation chain according to the following formulat，
Vt＝N1VOtmt
Wherein, VOtIs the DC voltage of the energy storage submodule, mtFor storing energyModulation ratio of the sub-module;
with the collected grid voltage effective value vector VsThe starting end of the device is a circle center and VtForming a first circle as a radius;
calculating the output voltage V of the energy-free commutation chain according to the following formulac，
Vc＝N2VOcmc
Wherein VOcIs the DC voltage of the no-energy-storage submodule, mcModulating ratio for the energy-free submodule;
by the mains voltage VsThe end of the effective value vector is the center of a circle, VcIs a radius, forming a second circle;
and calculating the maximum active power value according to the position relation of the first circle and the second circle.
FIG. 3A shows a schematic view of a first positional relationship of a first circle and the second circle according to an example embodiment of the present application; FIG. 3B shows a schematic diagram of a second positional relationship of the first circle and the second circle according to an example embodiment of the present application; FIG. 3C shows a third positional relationship diagram of the first circle and the second circle according to an example embodiment of the present application; FIG. 3D shows a fourth schematic positional relationship of the first circle and the second circle according to an example embodiment of the present application; fig. 3E shows a fifth positional relationship diagram of the first circle and the second circle according to an example embodiment of the present application.
There are five states of the positions of the first circle and the second circle, as shown in fig. 3A-3E. Referring to fig. 3A, when the first circle 301 includes the second circle 302, the maximum value P of the active power is calculated according to the following formulamax：
Pmax＝VSIe，
Wherein, VsAs a vector of net-work voltage significant values, IeIs the rated current of the converter chain.
Referring to fig. 3B, when the second circle 302 includes the first circle 301, the maximum value P of the active power is calculated according to the following formulamax：
Pmax＝VSIesinθ，
Wherein θ is a tangent vector from the center of the second circle 302 to the first circle and a vector VsThe included angle of (a).
Referring to fig. 3C, when the first circle 301 intersects the second circle 302, the active power maximum value may be determined according to the intersection position. Fig. 4A shows a schematic diagram of a first intersection location according to an example embodiment of the present application. Fig. 4B shows a second intersection position diagram according to an example embodiment of the present application. Fig. 4C shows a third intersection position diagram according to an example embodiment of the present application. The intersection positions are different, and the calculation methods of the maximum value of the active power are also different.
According to an example embodiment of the present application, vector V is shown in FIGS. 4A-4CsForm a vector V to the point of intersection 12tVector VsForm a vector V to the point of intersection 12c. Vector Vs、Vt、 VcForm a triangle, Vc、VsThe angle of (c) can be recorded as θ.
When theta is shown in FIG. 4A>At 90 deg., V can be adjustedcAnd VsPerpendicular to the direction ofsAnd VsAnd in parallel, the maximum active power output is achieved. As shown in fig. 4B, when θ is 90 °, VcAnd VsAnd the vertical direction Is and the parallel direction Is between Vs, and the maximum active power output Is naturally achieved. Therefore, when θ ≧ 90 °, the formula P is satisfiedmax＝VSIeAnd calculating the maximum value of the active power.
As shown in FIG. 4C, when θ < 90 °, V is calculated after forming a triangle with the position of the intersection 12sAnd VcThe closer the angle theta is to 90 degrees, the larger the output active power is. Wherein:
Figure GDA0003323604070000131
Pmax＝VSIe sinθ。
referring to fig. 3D, when the first circle 301 and the second circle 302 are tangent, the maximum value of active power PmaxIs 0. At this time, | Vc|+|Vt|＝|VSL, vector of current effective values due to current-converting chain IsAnd VcPerpendicular, VsAnd VcParallel, therefore IsAnd VsThe included angle is 90 deg., so the active power is 0.
Referring to fig. 3E, when the first circle 301 and the second circle 302 are separated from each other, the entire commutation chain is in a failure state and cannot run, and the operation needs to be stopped.
In step S220, the received active power command is modified according to the active power maximum value to obtain an active power modification command.
Firstly, the maximum value P of the active power is judgedmaxWhether or not greater than the active power command Pref；
When P is presentmax≥PrefThe active power modification instruction Pref’＝Pref；
When P is presentmax<PrefThe active power modification instruction Pref’＝Pmax。
In step S230, the received reactive power instruction is modified according to the active power modification instruction to obtain a reactive power modification instruction.
Firstly, correcting the instruction P according to the active powerref' and apparent power S of the converter chain, and calculating the maximum value Q of the reactive power of the converter chain according to the following formulamax：
Figure GDA0003323604070000141
Judging the maximum value Q of the reactive powermaxWhether or not greater than the reactive power command Qref；
When Q ismax≥QrefThen, the reactive power correction command Qref’＝Qref；
When Q ismax<QrefThen, the reactive power correction command Qref’＝Qmax。
In step S240, the control system allocates the active power correction instruction to the energy storage commutation chain, and allocates the reactive power correction instruction to the non-energy storage commutation chain and the energy storage commutation chain.
According to some embodiments of the present application, the reactive power correction instruction may be distributed to the energy storage commutation chain and the energy-free commutation chain according to a distribution principle of the reactive power correction instruction, where the distribution principle is based on a principle that efficiency of the power unit is optimal. Since the distribution proportion of the active power and the reactive power affects the efficiency of the power unit, the distribution relation of the reactive power can be selected according to the efficiency curve and the principle of optimal efficiency of the power unit.
According to other embodiments of the present application, the effective value vector I of the current of the converter chain may be based onsThe allocation is made in relation to the position of the second circle. Fig. 5A shows a reactive power distribution schematic according to a first example embodiment of the present application. Fig. 5B shows a reactive power distribution schematic according to a second example embodiment of the present application.
Firstly, according to the active power correction instruction Pref'. the reactive power correction command Qref' and grid voltage effective value vector VsAnd calculating the effective value of the current of the commutation chain. Define the clipping phi ═ arctan (Q)ref’/Pref'). By the effective value of the current, by VsThe included angle phi of the two-phase current-forming current effective value vector Is。
As shown in fig. 5A, when the current effective value vector IsOr the extension line thereof intersects or is tangent to the second circle 302, the reactive power correction command Q is transmittedref' are all assigned to the non-energy-storing commutation chain. I.e. the second reactive power modification command Q without energy storage commutation chain allocation2ref＝Qref', first reactive power correction command Q for energy storage commutation chain allocation1ref＝0。
When the current effective value vector I is shown in FIG. 5BsOr its extension line is away from the second circle 302, to a second reactive power of the non-energy-storing commutation chainRate correction instruction Q2ref＝Vc×IsA first reactive power modification command Q assigned to said energy storage commutation chain1ref＝Qref’-Q2ref. Namely, Qref' is preferentially allocated to the energy-free commutation chain, and the rest is allocated to the energy-storage commutation chain.
In fig. 5A and 5B, the output voltage V of the non-energy-storing commutation chaincCan be arbitrarily changed on an OA line segment and still satisfy Q2max＝Vc×Is，Q1ref＝Qref’-Q2ref。
In step S250, the energy storage commutation chain executes closed-loop control according to the distributed active power correction instruction and reactive power correction instruction; and the non-energy-storage current conversion chain executes closed-loop control according to the distributed reactive power correction instruction.
According to an example embodiment of the application, said control system in said converter chain is divided into two subsystems, namely: the first control subsystem controls the energy storage commutation chain; and the first control subsystem controls the energy-free commutation chain. The control system coordinates inputs and outputs of the first control subsystem and the second control subsystem. The energy storage current conversion chain has active and reactive adjusting capacity at the same time, and active power output is preferred. The non-energy-storage current conversion chain has reactive power regulation capability and takes priority on reactive power output.
The process that the energy storage commutation chain executes closed-loop control according to the distributed active power correction instruction and reactive power correction instruction comprises the following steps: taking the distributed active power correction instruction and reactive power correction instruction as an outer loop control target; obtaining a current instruction value of an inner ring by a regulator according to the difference value between the outer ring control target and the measured value; obtaining an output voltage set value by a difference value between the current instruction value and the current measured value through a regulator; distributing the given value of the output voltage to each energy storage sub-module; and each energy storage sub-module controls the output voltage according to the given value of the output voltage.
The process that the non-energy-storage current conversion chain executes closed-loop control according to the distributed reactive power correction instruction comprises the following steps: taking the direct-current voltage average value of the non-energy-storage converter submodule and the distributed reactive power as an outer ring control target; obtaining a current instruction value of an inner ring by a regulator according to the difference value between the outer ring control target and the measured value; the difference value between the current instruction value and the measured value is adjusted by a regulator to obtain an output voltage set value; distributing the given value of the output voltage to each energy-free submodule; and each energy-free sub-module controls the output voltage according to the given value of the output voltage.
In the above commutation chain control method, the energy storage submodule and the energy-free submodule may be switched with each other; the energy storage sub-module or the non-energy storage sub-module may be converted to a fault bypass sub-module. That is, N1, N2, and N3 can be dynamically changed, N1 and N2 can be changed in both directions, N1 or N2 can be changed in one direction to N3, and N1+ N2+ N3 is equal to N. Therefore, the number of the sub-modules with energy storage, the sub-modules without energy storage and the sub-modules with fault bypass can be adjusted according to the control requirement.
In the operation process, when an energy storage unit in the energy storage submodule has a fault, the isolating switch is separated or the DC/DC loop is locked, and the energy storage submodule is converted into an energy-free submodule; updating the number N of the energy storage sub-modules1And the number N of said energy-free submodules2(ii) a And repeating the steps in the current conversion chain control method, so that the distribution relation of the active power instruction and the reactive power instruction can be updated.
Similarly, when a power unit in the energy storage sub-module fails, the bypass switch is closed, and the energy storage sub-module is converted into a fault bypass sub-module; when a power unit in the non-energy-storage sub-module fails, the bypass switch is closed, and the non-energy-storage sub-module is converted into a fault bypass sub-module; updating the number N of the energy storage sub-modules1And the number N of said energy-free submodules2(ii) a The steps in the commutation chain control method are repeated, and the distribution relation of the active power instruction and the reactive power instruction can also be updated.
Fig. 6 shows a flow chart of a commutation chain control method according to another example embodiment of the present application.
According to another embodiment of the present application, there is also provided a commutation chain control method, including:
in step S610, according to the number N of the energy storage sub-modules1And the number N of said energy-free submodules2Respectively calculating the output voltage V of the energy storage commutation chaintAnd the output voltage V of the non-energy-storage converter chainc。
In step S620, the collected grid voltage effective value vector V is usedsRespectively takes the initial end as the circle center and respectively takes Vt、VcForming a first circle and a second circle for the radius, and calculating the maximum value P of the active power output by the commutation chain according to the position relation of the first circle and the second circlemax。
In step S630, the maximum value P of the active power is determinedmaxFor received active power command PrefCorrecting to obtain an active power correction instruction Pref’。
In step S640, the command P is modified according to the active powerref' and apparent power S of said converter chain, for received reactive power command QrefCorrecting to obtain a reactive power correction instruction Qref’。
In step S650, an active power modification command Pref' is assigned to the energy storage commutation chain.
In step S660, the command P is modified according to the active powerref', reactive power correction command Qref' and a vector of voltage effective values VsCalculating the current I of the converter chainsValue and direction, and according to current IsDetermining a reactive power correction command Q according to the position relation between the value and the direction and the second circleref' distribution principle.
In step S670, according to the distribution principle, the reactive power correction command Q is sentref' to the non-energy-storage commutation chain and the energy-storage commutation chain.
In step S680, the energy storage commutation chain and the non-energy storage commutation chain execute closed-loop control according to the allocated active power correction instruction and/or reactive power correction instruction.
Fig. 7 shows a flow chart of a converter control method according to an example embodiment of the present application.
According to another aspect of the present application, a converter control method is also provided. The converter comprises three active modular converter chains 1000 in fig. 1A, which are A, B, C three-phase converter chains respectively. As shown in fig. 7, the inverter control method includes:
in step S710, the numbers N of energy storage sub-modules of the A, B, C three-phase commutation chains are respectively read1A、N1B、N1CAnd the number N of energy-storage-free sub-modules2A、N2B、N2C。
In step S720, the numbers of the energy storage submodules and the energy-free submodules in the A, B, C three-phase commutation chain are respectively adjusted, so that the numbers of the energy storage submodules in the A, B, C three-phase commutation chain are all N1minThe number of the energy-storage-free sub-modules is N2minAnd the following conditions are satisfied:
N1min＝min(N1A；N1B；N1C)
N2min＝min(N2A+N1A-N1min；N2B+N1B-N1min；N2C+N1C-N1min)。
e.g. N1A＝8、N2A＝2、N1B＝6、N2B＝3、N1C＝9、N2C＝1。N1min＝min(N1A；N1B；N1C)＝min(8；6；9)＝6。N2min＝min(4；3；4)＝3。
For the a-phase converter chain, 1 of the 8 energy storage sub-modules may be converted into an energy-free sub-module, and 1 may be converted into a fault bypass sub-module. Converted N1A＝8-1-1＝6， N 2A2+ 1-3. For a B-phase current chain, it may remain unchanged. For the C-phase converter chain, 2 of the 9 energy storage sub-modules may be converted into energy-free sub-modules, 1 may be converted into a fault bypass sub-module, and N is obtained after the conversion1A＝9-2-1＝6，N2A1+ 2-3. In this way, the same quantity of ABC three-phase converter chain energy storage sub-modules and energy-free sub-modules is realized.
In step S730, the number N of the energy storage sub-modules of the A, B, C three-phase converter chain is determined1minAnd the number N of energy-storage-free sub-modules2minExecuting the above-mentioned converter chain control method, so that the A, B, C three-phase converter chain outputs active power balance;
in step S740, when the number of the energy storage sub-modules or the number of the energy storage sub-modules of the A, B, C three-phase converter chain is changed, the above steps are repeated.
When three-phase converter chains are combined, the power balance of three phases needs to be considered, and higher requirements are put on the control of the converter chains. According to the method for controlling the three-phase converter chain, the three-phase power is balanced by controlling the number of the submodules in the three-phase converter chain.
Fig. 8 shows a block diagram of the composition of a commutation chain control device according to an exemplary embodiment of the present application.
According to another aspect of the present application, there is also provided a commutation chain control apparatus 800, which includes an active power maximum value calculation module 810, an active power command modification module 820, a reactive power command modification module 830, a power command allocation module 840, and a power command execution module 850.
An active power maximum calculation module 810, configured to calculate the maximum value according to the number N of the energy storage sub-modules1And the number N of said energy-free submodules2Calculating the maximum value of the active power output by the current conversion chain;
an active power instruction modification module 820, configured to modify the received active power instruction according to the maximum active power value to obtain an active power modification instruction;
the reactive power instruction correction module 830 is configured to correct the received reactive power instruction according to the active power correction instruction to obtain a reactive power correction instruction;
a power instruction allocation module 840, configured to allocate the active power correction instruction to the energy storage commutation chain and allocate the reactive power correction instruction to the non-energy-storage commutation chain and the energy storage commutation chain by the control system;
and the power instruction execution module 850 is configured to execute closed-loop control by the energy storage commutation chain according to the distributed active power correction instruction and reactive power correction instruction, and execute closed-loop control by the non-energy storage commutation chain according to the distributed reactive power correction instruction.
According to some embodiments of the present application, the commutation chain control apparatus 800 further comprises: a first control submodule and a second control submodule. The first control submodule controls the energy storage commutation chain; the first control submodule controls the non-energy-storage current conversion chain; the commutation chain control apparatus 800 coordinates the input and output of the first control sub-module and the second control sub-module.
Fig. 9 is a block diagram showing a configuration of a converter control apparatus according to an exemplary embodiment of the present application.
According to another aspect of the present application, there is also provided a converter control apparatus 900, including: a sub-module number reading module 910, a sub-module number adjusting module 920, and a power correcting and allocating module 930.
The submodule quantity reading module 910 is configured to read the quantity of the energy storage submodules and the quantity of the energy-free submodules of the A, B, C three-phase commutation chain respectively;
the submodule quantity adjusting module 920 is configured to respectively adjust the quantities of the energy storage submodules and the energy-free submodules in the A, B, C three-phase converter chain;
and a power correction and distribution module 930, configured to execute the commutation chain control method according to the number of energy storage submodules and the number of energy-free submodules of the A, B, C three-phase commutation chain.
According to another aspect of the present application, there is also provided an active modular converter control electronics comprising: one or more processors; storage means for storing one or more programs; when executed by the one or more processors, cause the one or more processors to implement the converter control method described above.
According to the commutation chain control method, the output voltages of the two commutation chains are calculated according to the number of the energy storage submodules and the number of the energy-free submodules, the vector diagram is drawn, the actual output active power capability of the commutation chain is confirmed through the position relation of two circles in the vector diagram, and the method is concise, visual and high in operability. In addition, the power instruction is corrected according to the actual output active power capability of the converter chain, so that the control target can be prevented from exceeding the running range of the converter chain, and the reliability is improved. On the basis of instruction correction, on the premise of meeting the control target, the converter chain is operated at the optimal working point through reasonable distribution of reactive power diameter, and the optimal operation efficiency is ensured. Finally, in the control method of the converter, the output active power of the three-phase conversion chain is balanced by adjusting the number of the energy storage sub-modules and the number of the energy-free sub-modules in the three-phase conversion chain, and the realization of the control target of the single-phase conversion chain and the balance of the three-phase active power are considered.
The foregoing detailed description of the embodiments of the present application has been presented to illustrate the principles and implementations of the present application, and the description of the embodiments is only intended to facilitate the understanding of the methods and their core concepts of the present application. Meanwhile, a person skilled in the art should, according to the idea of the present application, change or modify the embodiments and applications of the present application based on the scope of the present application. In view of the above, the description should not be taken as limiting the application.

Claims (23)

1. An active modular converter chain control method, wherein the converter chain comprises,
n sub-modules connected in series, wherein N is an integer greater than or equal to 2;
the N sub-modules comprise N1Energy storage submodule N2Each energy-free submodule and N3A fault bypass submodule, N1、N2Is an integer of 1 or more, N3Is an integer of 0 or more;
the energy storage sub-module comprises a power unit, an isolation unit and an energy storage unit; said N is1Each energy storage submodule forms an energy storage commutation chain;
the non-energy-storage sub-module comprises a power unit; said N is2Each energy-free submodule forms an energy-free commutation chain;
the power cell includes a bypass switch;
the method for controlling the converter chain is characterized by comprising the following steps:
according to the number N of the energy storage sub-modules1Calculating the output voltage V of the energy storage commutation chaint；
The number N of the energy-free sub-modules2Calculating the output voltage V of the non-energy-storage current conversion chainc；
Respectively using the collected effective value vector V of the network voltagesWith the start and end of V as the center of a circletAnd said VcIs a radius, forming two circles;
calculating the maximum value of the active power output by the current conversion chain according to the position relation of the two circles;
correcting the received active power instruction according to the active power maximum value to obtain an active power correction instruction;
correcting the received reactive power instruction according to the active power correction instruction to obtain a reactive power correction instruction;
distributing the active power correction instruction to the energy storage commutation chain, and distributing the reactive power correction instruction to the non-energy storage commutation chain and the energy storage commutation chain;
the energy storage commutation chain executes closed-loop control according to the distributed active power correction instruction and reactive power correction instruction; and the non-energy-storage current conversion chain executes closed-loop control according to the distributed reactive power correction instruction.
2. The method of claim 1, wherein the two circles comprise:
a first circle with a vector V of effective values of said grid voltagesThe starting end of the V is the circle centertIs the radius;
a second circle with the grid voltage effective value vector VsThe tail end of the V is the center of a circlecIs a radius.
3. The method of controlling a converter chain according to claim 2, further comprising:
calculating the output voltage V of the energy storage commutation chain according to the following formulatAnd the output voltage V of the non-energy-storage converter chainc：
Vt＝N1VOtmt；
Vc＝N2VOcmc；
Wherein VOtIs the DC voltage of the energy storage submodule, mtThe modulation ratio of the energy storage submodule is used; vOcIs the DC voltage of the no-energy-storage submodule, mcAnd modulating the ratio for the energy-free submodule.
4. The method according to claim 2, wherein said calculating said active power maximum value based on the positional relationship between said first circle and said second circle comprises:
when the first circle comprises the second circle, calculating the maximum value P of the active power according to the following formulamax：
Pmax＝VSIe，
Wherein, VsFor collected grid voltage vectors, IeThe rated current of the converter chain is obtained;
when the second circle comprises the first circle, calculating the maximum value P of the active power according to the following formulamax：
Pmax＝VSIesinθ，
Wherein θ is a tangent vector from the center of the second circle to the first circle and a vector VsThe included angle of (A);
when the first circle intersects with the second circle, determining the maximum value of the active power according to the intersection point position;
when the first circle and the second circle are tangent, the maximum active power value is 0;
when the first circle and the second circle are separated from each other, the commutation chain is in a fault state.
5. The method according to claim 4, wherein said determining said active power maximum value according to the position of the intersection point when said first circle intersects said second circle comprises:
calculating the maximum value P of the active power according to the following formulamax：
When theta is more than or equal to 90 degrees, Pmax＝VSIe；
When theta is less than 90 DEG, Pmax＝VSIesinθ；
Wherein θ is a vector from the center of the second circle to the intersection and a vector VsThe included angle of (a).
6. The method according to claim 2, wherein the modifying the received active power command according to the active power maximum value to obtain an active power modification command comprises:
judging the maximum value P of the active powermaxWhether or not greater than the active power command Pref；
When P is presentmax≥PrefThe active power modification instruction Pref’＝Pref；
When P is presentmax<PrefThe active power modification instruction Pref’＝Pmax。
7. The method according to claim 6, wherein the step of modifying the received reactive power command according to the active power modification command to obtain a reactive power modification command comprises:
according to the active power correction instruction Pref' and apparent power S of the converter chain, and calculating the maximum value Q of the reactive power of the converter chain according to the following formulamax：
Figure FDA0003323604060000031
Judging the maximum value Q of the reactive powermaxWhether or not greater than the reactive power command Qref；
When Q ismax≥QrefThen, the reactive power correction command Qref’＝Qref；
When Q ismax<QrefThen, the reactive power correction command Qref’＝Qmax。
8. The converter chain control method according to claim 7, wherein the step of assigning the reactive power correction command to the non-energy-storage converter chain and the energy-storage converter chain comprises:
according to the active power correction instruction Pref'. the reactive power correction command Qref' and grid voltage effective value vector VsCalculating the current effective value of the current conversion chain;
according to the formula VsPhi is arctan (Q)ref’/Pref') determining the direction and thus the vector of current effective values Is；
When the current effective value vector IsOr the extension line of the reactive power correction command Q is intersected or tangent with the second circleref' all assigned to said non-energy-storing commutation chain;
when the current effective value vector IsOr when the extension line of the second reactive power correction instruction is separated from the second circle, distributing the second reactive power correction instruction Q to the energy-free commutation chain2ref＝Vc×IsA first reactive power modification command Q assigned to said energy storage commutation chain1ref＝Qref’-Q2ref。
9. The converter chain control method according to claim 1, wherein the step of assigning the reactive power correction command to the non-energy-storage converter chain and the energy-storage converter chain comprises:
and distributing the reactive power correction instruction to the energy storage commutation chain and the energy-free commutation chain according to the principle that the efficiency of the power unit is optimal.
10. The method of claim 1,
the energy storage sub-module and the energy-free sub-module can be mutually converted;
the energy storage sub-module or the non-energy storage sub-module may be converted to a fault bypass sub-module.
11. The converter chain control method according to claim 1, wherein the energy storage converter chain performs closed-loop control according to the distributed active power correction command and reactive power correction command, and the method comprises the following steps:
taking the distributed active power correction instruction and reactive power correction instruction as an outer loop control target;
obtaining a current instruction value of an inner ring by a regulator according to the difference value between the outer ring control target and the measured value;
obtaining an output voltage set value by a difference value between the current instruction value and the current measured value through a regulator;
distributing the given value of the output voltage to each energy storage sub-module;
and each energy storage sub-module controls the output voltage according to the given value of the output voltage.
12. The converter chain control method according to claim 1, wherein the energy-free converter chain performs closed-loop control according to the distributed reactive power correction command, and the method comprises the following steps:
taking the direct-current voltage average value of the non-energy-storage converter submodule and the distributed reactive power as an outer ring control target;
obtaining a current instruction value of an inner ring by a regulator according to the difference value between the outer ring control target and the measured value;
the difference value between the current instruction value and the measured value is adjusted by a regulator to obtain an output voltage set value;
distributing the given value of the output voltage to each energy-free submodule;
and each energy-free sub-module controls the output voltage according to the given value of the output voltage.
13. The method of converter chain control according to claim 1, wherein said isolation unit comprises:
an isolation switch and/or a DC/DC loop with an isolation function.
14. The method according to claim 1, wherein the power unit comprises a direct current capacitor and a bridge circuit, and the bridge circuit comprises a half-bridge circuit formed by two groups of power semiconductor devices or a full-bridge circuit formed by four groups of power semiconductor devices.
15. The method of converter chain control according to claim 13, further comprising:
when an energy storage unit in the energy storage sub-module fails, the isolating switch is separated or the DC/DC loop is locked, and the energy storage sub-module is converted into an energy-free sub-module;
updating the number N of the energy storage sub-modules1And the number N of said energy-free submodules2；
Repeating the steps of claim 1.
16. The method of converter chain control according to claim 1, further comprising:
when a power unit in the energy storage sub-module fails, the bypass switch is closed, and the energy storage sub-module is converted into a fault bypass sub-module;
when a power unit in the non-energy-storage sub-module fails, the bypass switch is closed, and the non-energy-storage sub-module is converted into a fault bypass sub-module;
updating the number N of the energy storage sub-modules1And the energy-storage-free sub-dieNumber of blocks N2；
Repeating the steps of claim 1.
17. An active modular converter chain control method, wherein the converter chain comprises,
n sub-modules connected in series, wherein N is an integer greater than or equal to 2;
the N sub-modules comprise N1Energy storage submodule N2Each energy-free submodule and N3A fault bypass submodule, N1、N2Is an integer of 1 or more, N3Is an integer of 0 or more;
the energy storage sub-module comprises a power unit, an isolation unit and an energy storage unit; said N is1Each energy storage submodule forms an energy storage commutation chain;
the non-energy-storage sub-module comprises a power unit; said N is2Each energy-free submodule forms an energy-free commutation chain;
the power cell includes a bypass switch;
the method for controlling the converter chain is characterized by comprising the following steps:
according to the number N of the energy storage sub-modules1And the number N of said energy-free submodules2Respectively calculating the output voltage V of the energy storage commutation chaintAnd the output voltage V of the non-energy-storage converter chainc；
With the collected grid voltage effective value vector VsRespectively takes the initial end as the circle center and respectively takes Vt、VcForming a first circle and a second circle for the radius, and calculating the maximum value P of the active power output by the commutation chain according to the position relation of the first circle and the second circlemax；
According to the maximum value P of active powermaxFor received active power command PrefCorrecting to obtain an active power correction instruction Pref’；
According to the active power correction instruction Pref' and apparent power S of said converter chain, for received reactive power command QrefCorrecting to obtain a reactive power correction instruction Qref’；
Distributing an active power correction instruction Pref' to the energy storage commutation chain;
according to the active power correction instruction Pref', reactive power correction command Qref' and a vector of voltage effective values VsCalculating the current I of the converter chainsValue and direction, and according to current IsDetermining a reactive power correction command Q according to the position relation between the value and the direction and the second circleref' distribution principle;
according to the distribution principle, correcting the reactive power instruction Qref' assigning to the non-energy-storage commutation chain and the energy-storage commutation chain;
and the energy storage commutation chain and the non-energy storage commutation chain execute closed-loop control according to the distributed active power correction instruction and/or reactive power correction instruction.
18. A method for controlling an active modular converter, wherein the converter comprises three active modular converter chains, respectively A, B, C three-phase converter chains, wherein the converter chains comprise,
n sub-modules connected in series, wherein N is an integer greater than or equal to 2;
the N sub-modules comprise N1Energy storage submodule N2Each energy-free submodule and N3A fault bypass submodule, N1、N2Is an integer of 1 or more, N3Is an integer of 0 or more;
the energy storage sub-module comprises a power unit, an isolation unit and an energy storage unit; said N is1Each energy storage submodule forms an energy storage commutation chain;
the non-energy-storage sub-module comprises a power unit; said N is2Each energy-free submodule forms an energy-free commutation chain;
the power cell includes a bypass switch;
the converter control method is characterized by comprising the following steps:
respectively reading the number N of energy storage sub-modules of the A, B, C three-phase converter chain1A、N1B、N1CAnd the number N of energy-storage-free sub-modules2A、N2B、N2C；
Respectively adjusting the number of energy storage submodules and the number of energy-free submodules in the A, B, C three-phase commutation chain, so that the number of the energy storage submodules in the A, B, C three-phase commutation chain is N1minThe number of the energy-storage-free sub-modules is N2minAnd the following conditions are satisfied:
N1min＝min(N1A；N1B；N1C)
N2min＝min(N2A+N1A-N1min；N2B+N1B-N1min；N2C+N1C-N1min)；
according to the number N of the energy storage sub-modules of the A, B, C three-phase converter chain1minAnd the number N of energy-storage-free sub-modules2minPerforming the commutation chain control method of any one of claims 1-17, such that said A, B, C three-phase commutation chain outputs are power balanced;
and when the number of the energy storage sub-modules or the number of the energy storage sub-modules of the A, B, C three-phase converter chain is changed, repeating the steps.
19. The converter control method of claim 18 wherein said A, B, C three-phase converter chain output active power balancing comprises:
the active power output by each A, B, C three-phase converter chain is equal.
20. An active modular converter chain control device, wherein the converter chain comprises,
n sub-modules connected in series, wherein N is an integer greater than or equal to 2;
the N sub-modules comprise N1Energy storage submodule N2Each energy-free submodule and N3A fault bypass submodule, N1、N2Is an integer of 1 or more, N3Is an integer of 0 or more;
the energy storage submodule comprises a power unit and an isolation unitAnd an energy storage unit; said N is1Each energy storage submodule forms an energy storage commutation chain;
the non-energy-storage sub-module comprises a power unit; said N is2Each energy-free submodule forms an energy-free commutation chain;
the power cell includes a bypass switch;
characterized in that the commutation chain control device comprises:
an active power maximum value calculation module used for calculating the number N of the energy storage sub-modules1And the number N of said energy-free submodules2Calculating the maximum value of the active power output by the current conversion chain;
the active power instruction correction module is used for correcting the received active power instruction according to the maximum value of the active power to obtain an active power correction instruction;
the reactive power instruction correction module is used for correcting the received reactive power instruction according to the active power correction instruction to obtain a reactive power correction instruction;
the power instruction distribution module is used for distributing the active power correction instruction to the energy storage commutation chain and distributing the reactive power correction instruction to the non-energy-storage commutation chain and the energy storage commutation chain;
and the power instruction execution module is used for executing closed-loop control by the energy storage commutation chain according to the distributed active power correction instruction and reactive power correction instruction and executing closed-loop control by the non-energy storage commutation chain according to the distributed reactive power correction instruction.
21. The commutation chain control device of claim 20, further comprising:
the first control submodule controls the energy storage commutation chain;
the second control submodule controls the non-energy-storage current conversion chain;
and the commutation chain control device coordinates the input and the output of the first control submodule and the second control submodule.
22. An active modular converter control arrangement, wherein said converter comprises three active modular converter chains, respectively A, B, C three-phase converter chains, wherein said converter chains comprise,
n sub-modules connected in series, wherein N is an integer greater than or equal to 2;
the N sub-modules comprise N1Energy storage submodule N2Each energy-free submodule and N3A fault bypass submodule, N1、N2Is an integer of 1 or more, N3Is an integer of 0 or more;
the energy storage sub-module comprises a power unit, an isolation unit and an energy storage unit; said N is1Each energy storage submodule forms an energy storage commutation chain;
the non-energy-storage sub-module comprises a power unit; said N is2Each energy-free submodule forms an energy-free commutation chain;
the power cell includes a bypass switch;
characterized in that the converter control device comprises:
the submodule quantity reading module is used for respectively reading the quantity of the energy storage submodules and the quantity of the energy-free submodules of the A, B, C three-phase commutation chain;
the submodule quantity adjusting module is used for respectively adjusting the quantity of the energy storage submodules and the quantity of the energy-free submodules in the A, B, C three-phase converter chain;
and the power correction and distribution module is used for executing the commutation chain control method of claim 1 according to the number of the energy storage sub-modules and the number of the energy-free sub-modules of the A, B, C three-phase commutation chain.
23. An active modular converter control electronics comprising:
one or more processors;
storage means for storing one or more programs;
when executed by the one or more processors, cause the one or more processors to implement the converter control method of claim 18.
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